The invention is related to a design of microstrip antenna and particularly related to a microstrip antenna having an integral feed structure and multiple radiating elements.
In the field of wireless communication technology, an antenna is a component to receive and transmit electromagnetic wave. A good antenna can increase the efficiency, sensitivity and reliability of a wireless communication system. Hence, a good design of an antenna having high performance is an important part of the wireless communication system.
With the advancement of integrated circuit technology, the wireless products such as the mobile terminals become smaller in size. As they get small-sized and high-graded, newer antennas are desired. Microstrip antennas have been presented as one special research and product development area in the telecommunication field.
The concept of microstrip antennas was proposed in early 1950s, and became commercially viable in 1970s. A microstrip antenna is light, small and easy to be manufactured. Microstrip antennas can be easily attached to an object moving at a high speed. Because of these characteristics, microstrip antennas are widely applied on the fields of satellite communication, global positioning system, and low-power personal communication.
Typically, the microstrip antenna has a better efficiency when a dielectric constant becomes lower, and a substrate becomes thicker. Also, since the microstrip antenna has a high efficiency when using a high frequency, it can be considered as the very good choice for satisfying the miniaturization requirement for portable communication tool such as cell phones.
A microstrip antenna has several advantages. The first advantage is that the radiation of electromagnetic wave emits from a single side of the antenna so as to reduce the impact of electromagnetic wave on human body. Another advantage is that a microstrip antenna has a simple structure which is easy to construct. Another advantage is that the microstrip antenna can be designed on a circuit board together with solid-state modules such as an oscillator, amplifying circuit, variable attenuator, switch, modulator, mixer, or phase shifter. The microstrip antenna can also be manufactured at a low cost with a small size and a light weight, and thus it is suitable to mass production.